The present invention relates to a drive roller, in particular for drive belts of a thread supply device on a textile machine.
A drive roller of the above mentioned type is used in particular on round knitting machines and in connection with so-called band furnishing. It serves for driving an endless drive belt, which lies with a preselected surrounding angle on the supporting bodies arranged on the periphery of the drive roller as well as a plurality of thread supply rollers which are determined for example for slippage-free positive supply of threads guided between the drive belt and the associated supply rollers. This is disclosed for example in the German patent document DE PS1 143, 294. Alternatively, it is possible to drive with the drive belts separate additional rollers which are mounted on the supply rollers or other thread supply devices than the described band furnishing. A change of the thread supply speed can bring about the diameter change of the drive roller via a radial displacement of the supporting bodies which as a rule is not possible with the tensioned drive belts and therefore is possible only in an immovable position of the drive roller and in an immovable position of the round knitting machine. This is disclosed for example in the German patent document DE-PS1 2 208, DE-PS1 286 680.
In addition, a drive roller of the above mentioned type is known whose adjusting device makes possible a relative turning of both disks also with the tensioned drive belts and thereby a continuous turning of the drive roller, or in other words with the running round knitting machine or in any operational position of the round knitting machine. This is disclosed for example in the German patent documents DE-OS 20 30 333 and DE 39 31 997 81. However, it is necessary here to provide a special easy turnability of both disks relative to one another, which is not suitable for the conventionally used drive rollers. They have as a rule two disks which are arranged at a distance from one another and are provided with radial or spiral guiding grooves in the facing wide sides. The supporting bodies are supported for example completely or partially in the radial guiding grooves of the one disk, and the guiding pins extend into the spiral guiding grooves of the other disk. Because of this construction, the supporting bodies are relatively thick.
In order to make possible a relatively great adjusting region with an increasing total diameter of the disks, the supporting bodies as a rule are moreover relatively short. As a result, the supporting bodies during their radial displacement have a tendency for tilting, edging and clamping, in particular when they must be adjusted against the tension of the drive belt and the contributing forces are engaged asymmetrically. This disadvantage is even more noticeable, the greater is the adjusted gap between the disks and the supporting bodies, required for turning of the disks. It is already known as disclosed in the German patent document DE 28 46 279 C2 to provide the drive rollers with means for reducing the tilting tendency and for this purpose the supporting bodies are formed asymmetrically and arranged with their diagonals in predetermined directions relative to the disk axis. In this known drive rollers however an adjustment of the supporting bodies is performed only with non-tensioned drive belts. In view of the automatic adjustment of the supporting bodies in any preselected operational region, the round knitting machine can not achieve any substantial advantages with such means.